Wii freezes when changing Widescreen settings from 16:9 to 4:3 and then back again.

I have a problem that you guys have probably never seen before. I've tried many things to fix it, including mauifrog's guide to fix a semi-brick but I still have no luck in fixing it.

I can enter the Wii settings menu fine, but after changing the widescreen settings from 16:9 to 4:3 and then back to 16:9, the Wii freezes up (black screen, high pitched continuous sound coming from TV).

I've got a launch model PAL Wii on 4.2e, bootmii installed, no system menu hacks, plenty of free blocks, this never used to happen - has only been happening in the last few months, have a genuine WiiKey v1 installed (from before HBC existed).

Upon restarting the Wii, the setting change (in this case going from 4:3 back to 16:9) has taken effect. It's important to note that this problem isn't limited to starting at 16:9, going to 4:3 and then back to 16:9 again. The opposite is also true.

In addition, it also occurs when changing the TV Type (ie, going from 480p to 480i and back again or even 480p->480i->576i and any combination of the three).

Bootmii is installed as boot2. I'll try your initial suggestion of performing a system format and see how it goes. If it fixes it, that'd be great, but it would be nice to know the reason for the problem so I can avoid it from happening again.

OK I actually figured out what was causing the problem. The reason it was happening is because I had a system menu hack on that changed the video mode to NTSC in AnyRegionChanger.

I initially thought all menu hacks were off because I use Startpatch for other menu hacks and only turned these off and forgot about AnyRegionchanger.

Note: To anyone wondering why I was using the video mode hack, it's because PAL virtual console games run slower than their NTSC counterpart and are 576i instead of 480p. By forcing NTSC video mode in AnyRegionChanger, you can install and run NTSC VC games on a PAL Wii without permanently changing it's region (ie, remaining on 4.2e).